In general, ink-jet inks are either dye- or pigment-based inks. Dye-based ink-jet inks generally use a soluble colorant that is usually water-based to turn the media a specific color. Alternatively, pigmented inks typically use a dispersed colorant to achieve color. In many cases, the line quality and accuracy of plots produced by pigment-based inks can be superior to that of dye-based inks. However, certain challenges exist with pigments because the colorant is present as a dispersion. With pigmented inks, solid particles are jetted with a vehicle and the solid particles adhere to the surface of the substrate. Once the water in the solution has evaporated, the particles will generally not redisperse, thereby producing a dried image.
As dye-based ink-jet inks have typically provided line quality and accuracy of plots that are generally inferior to pigment-based ink-jet inks, there has been increased interest in improving print quality resulting from the use of dye-based ink-jet inks. One problem associated with reduced line quality and accuracy of plots of dye-based ink-jet inks is directly related to a shorter-term problem associated with capping or decap, as well as longer-term problem associated with recovery. To avoid the problems associated with decap, pens are fired periodically at times other than when printing on a desired substrate, resulting in wasted ink-jet ink. The time between two firings is called slewing time. Thus, by increasing slewing time, less ink-jet ink is wasted and the ink-jet printer does not have to work as hard. One method of increasing slewing time that is known in the prior art is to increase the kinetic energy of the drop ejected from the pen. However, increasing the kinetic energy also tends to increase the spray, drop weight, and/or other image quality degrading characteristics. Further, this strategy does not work when a printer is turned off, or is unplugged. Thus, pen clogging related to longer-term recovery is also a problem in the ink-jet arts. As such, it would be desirable to provide ink-jet ink formulations that maintain good image quality when printed with reduced decap resulting from slewing, as well as after longer periods during extended power down. It would also be desirable to provide ink-jet inks that perform well in systems that utilize salts, as well as in systems of a more traditional nature.